[Zope] how to modify documents creation date

Hello, I need to modify the creation date of several documents: most of them a news, so I have to insert/modify to make them appear to bo created some time ago. Someone told me it can't be done in plone or zmi, but using scripting: ok, I believe it, but I think it's quite strange that no one else had to insert an old (forgotten) news in a plone site. Thanks in advance. zenobito. p.s.: I have zope 2.7.2, plone 2.0.5, ubuntu linux.